arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2310.20171astro-ph.SR
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Joy定律和平均倾角对磁通量浮现阶段的依赖性

The Dependence of Joy's Law and Mean Tilt as a Function of Flux Emergence Phase

Lucy W. Will, Aimee A. Norton, Jon Todd Hoeksema

AI总结:

本文利用MDI和HMI长达27年的观测数据,研究第23、24太阳周双极活动区倾角随磁通量浮现阶段的演化,发现平均倾角随磁通量浮现比例增加而增大,且第24周平均倾角大于第23周,但Joy定律斜率无显著周际差异。

摘要:

本文分析了1996年至2023年期间来自迈克尔逊多普勒成像仪(MDI)和日震与磁成像仪(HMI)的数据,以研究第23、24太阳周以及第25太阳周一部分期间双极磁区的倾角(γ)和Joy定律。利用HMI径向磁场(B_r)和MDI磁图(B_los)数据,通过正、负极性磁通量加权质心计算倾角(γ)。每个活动区(AR)只采样一次。分析仅包括Beta(β)类活动区,因为计算复杂活动区的γ意义较小。在活动区浮现过程中,我们发现平均倾角(γ̄)从20%磁通量浮现时的3.30°±0.75增加到活动区达到最大磁通量时的6.79°±0.66。第24太阳周的平均倾角γ̄_24=6.67±0.66大于第23太阳周的γ̄_23=5.11±0.61。在活动区达到最大磁通量时或穿过中央子午线时进行采样,Joy定律的斜率或γ̄均未发现显著差异。南北半球的γ̄存在持续差异,南半球在第23和24太阳周具有更高的γ̄,但不确定性使得这些差异在统计上不显著。

英文摘要:

Data from the Michelson Doppler Imager (MDI) and Helioseismic and Magnetic Imager (HMI) are analyzed from 1996 to 2023 to investigate tilt angles ($γ$) of bipolar magnetic regions and Joy's Law for Cycles 23, 24, and a portion of 25. The HMI radial magnetic field ($B_{r}$) and MDI magnetogram ($B_{los}$) data are used to calculate ($γ$) using the flux-weighted centroids of the positive and negative polarities. Each active region (AR) is only sampled once. The analysis includes only Beta ($β$)-class active regions since computing $γ$ of complex active regions is less meaningful. During the emergence of the ARs, we find that the average tilt angle ($\barγ$) increases from 3.30$^{\circ}\pm$0.75 when 20\% of the flux has emerged to 6.79$^{\circ}\pm$0.66 when the ARs are at their maximum flux. Cycle 24 had a larger average tilt $\barγ_{24}$=6.67$\pm$0.66 than Cycle 23, $\barγ_{23}$=5.11$\pm$0.61. No significant difference is found in the slope of Joy's law or $\barγ$ when sampling the ARs at the time of maximum flux or central meridian crossing. There are persistent differences in $\barγ$ in the hemispheres, with the southern hemisphere having higher ${\barγ}$ in Cycles 23 and 24, but the uncertainties are such that these differences are not statistically significant.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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